Parking in the sun: what it ruins and what to do about it

Sunlight is the slowest and most persistent destroyer of a car. It produces no symptoms and lights no lamps, and the result becomes visible years later in several places at once.

What suffers

Lacquer and paint. Ultraviolet breaks down the clear coat; it hazes and then begins to peel. Horizontal surfaces suffer fastest: roof, bonnet, boot lid.

Dashboard plastics. They fade, crack, and start creaking. A cracked dashboard is cosmetic damage that cannot be repaired locally.

Rubber seals — they dry out, harden, and stop sealing; then come wind noise and water in the cabin; covered in the door seals article.

Leather and fabric — they fade and lose flexibility.

Headlights — polycarbonate hazes and light output falls several times over; covered in the headlights article.

Tyres — rubber ages faster under ultraviolet.

The battery — it degrades in the heat and the failure appears in winter; covered in the summer heat article.

Cabin temperature

Inside a closed car in the sun the temperature is far above ambient and rises quickly.

The consequences:

• Plastics and adhesive mountings creep.
• Dashboard electronics degrade — a dash cam with a lithium battery swells.
• A phone in a mount overheats; covered in the phone mount article.
• An animal in the car faces a direct risk to life; covered in the pets article.

What genuinely works

Shade — obvious, but the only measure that works on every front at once. Choosing the spot is worth making a habit.

A windscreen sunshade — it lowers cabin temperature noticeably and protects the dashboard. The best effect-to-effort ratio available.

Side blinds — for rear passengers and the interior.

Tinting within the legal limits — it reduces heating and protects the trim.

Paint protection — regular application of a protective product; it extends lacquer life noticeably.

Plastic care — products with a UV filter, not glossy silicone dressings that attract dust.

Opening the windows a few millimetres where safe — it lowers the peak temperature.

What not to do

Covering the car on a sunny day without need — under a cover in wind, grit works as an abrasive; covered in the car cover article.

Washing in direct sunlight — water dries into spots and chemicals act more aggressively.

Leaving valuables on the dashboard — from a lighter to sunglasses: some are ruined, others invite trouble.

In short

• Sun destroys lacquer, plastics, rubber, headlights, and the battery at once.
• Cabin temperature far exceeds ambient and rises quickly.
• A windscreen shade is the best effect-to-effort measure.
• The battery degrades in summer and dies in winter.
• Do not wash in direct sunlight: spots and more aggressive chemistry.

Download the app — system voltage and codes are read with an ELM327 adapter over Bluetooth SPP on Android.